Rotary side heat sealer for packages



Feb. 10, 1953 v. G. WILLIAMS ROTARY SIDE HEAT; SEALER FOR PACKAGES 2 SHEETS-SHEET 1 Filed Dec. 26, 1947 :T'lUTTUT V/cfor G. Williams Feb. 10, 1953 v. G. WILLIAMS ROTARY S IDE HEAT SEALER FOR PACKAGES 2 SHEETS-QSHEET 2 Filed Dec. 26, 1947 Mm v Patented Feb. 10, 1953 ROTARY SIDE HEAT SEALER FOR PACKAGES Victor George Williams, Toronto, Ontario, Canada, assignor, by mesne assignments, to Delamere & Williams Company, Limited, Toronto,

Ontario, Canada Application December 26, 1947, Serial No. 793,945

3 Claims.

This invention relates generally to heat sealing machinery, and more particularly to a rotary heat sealer for the sealing of tea bags or similar packages along their vertical sides.

An object of this invention is to provide means for substantially continuous or regular sealing of the vertical sides of packages, thereby obviating the necessity of reciprocating action.

The foregoing and still further objects will become apparent from a study of the following specification, taken in conjunction with the accompanying drawings, wherein like characters of reference indicate corresponding parts throughout the several views and wherein Figure 1 is a vertical side view of a portion of a tea bagging machine showing in particular the outside heat sealing roller of the pair of sealing rollers.

Figure 2 is a horizontal section of the side sealing rollers on the line 22 in Figure 1.

Figure 3 is a vertical section taken through the axes of rotation of the side sealing rollers on the line 33 of Figure 1. Among other things, are shown here the air cylinder and associated lever mechanism for bringing the rollers into contact with the opposite sides of the bags to be sealed.

The construction of side sealing mechanism hereinafter fully described, is an improved construction over than disclosed in United States patent application No. 713,668 filed December 3, 1946, now Patent No. 2,556,382 applicants V. G. Williams et al., wherein the sealing of the vertical sides of the bags was accomplished by reciprocating action of heated elements rather than by the continuous rotation of heated ribbed rollers.

For an extensive description of the entire tea bagging machine, reference is made to the above mentioned United States application. However, for purposes of understanding this particular construction of rotary side sealing mechanism, a brief description of the entire machine follows.

The paper or other material from which the tea bags are formed is obtained in the form of a roll, one side of the paper carrying a thin nontoxic thermoplastic, which acts as an adhesive when subjected to a comparatively high temperature. The strip of paper as it unrolls passes through a plurality of fingers which form it into a V-shaped chanel, the adhesive coated surface being on the inside. Pairs of spring loaded fingers then close upon the paper, producing a plurality of individual pockets, into which is poured the desired uantity of tea. Just prior to the filling of the pockets, the originally continuous strip of paper is sheared transversely of its direction of supporting the bags then release them, and the.

bags are removed and ultimately deposited in a suitable receptacle,

The construction of the vertical side sealing rollers will now be described in detail, with reference to all the figures.

An outside roller 4 is bolted to spindle sleeve 5 which in turn is affixed to shaft 6. Loading on this shaft is taken by tapered roller bearings I and 8, and by housing 9.

Roller 4 which in the preferred construction is of Monel metal, is heated to a suitably high temperature by an electrically insulated resistance element I0 self supported in the form of a coil within the roller, but mechanically independent of rotation of the latter. The head of roller 4 is provided with an axial cavity ll into which thermostat I2 extends.

the temperature of the sealing roller in a Well known manner which is not shown since it does not form part of this invention. Disposed upon the periphery of drum 4 in planes parallel to the axis of rotation of the roller are a plurality of equally spaced ribs IS, the purpose of which will be subsequently de-. scribed.

An inner roller I4 carrying bearings l5, 15,

rotates upon axle l6 which is fixed to carriage l1.

Disposed upon the periphery of roller I4 are a plurality of ribs l8 which correspond in number and placement to the ribs l3 on roller 4. The outer surfaces of ribs 18 carry retaining grooves l9 running longitudinally of the ribs. members 20 are supported upon the outer surfaces of ribs l8 by means of tongues 21 which are gripped by grooves Hi. In the preferred construction resilient members 20 are made of neoprene,

a synthetic rubber which withstands high temperatures and pressures, without losing itselasticity or shape. synchronized with that of outer drum 4 by means Thermostat I2 is supported upon bracket l2 and is adapted to control Resilient Rotation of inner drum I4 is of gears 22 and 23, so that bearing surfaces 24 and 25 of resilient rib members 20 and ribs l3 respectively, co-act and press firmly together, transversely of the direction of movement of the carrier, against opposite sides of the containers to be sealed.

The degree of pressure which is exerted upon each rib by the corresponding rib on the other roller is determined by the spacing of the axles 6 and I 6 supporting the rollers. The former rests upon bearings I and 8 within housing 9, so that it is capable only of rotation, whereas the latter rests upon bearings which are attached to carriage l1 and therefore. is capable of translation as well as of rotation. Carriage I! reciprocates horizontally upon bed 26 in a plane containing the axes of rotation of rollers 4 and I4, so as to vary the spacing between the two axes.

The actual position of carriage l1 upon bed 26 is controlled by an, air cylinder 21 and an associated lever mechanism designated generally as 28. When the packaging machine is in operation, air pressure is supplied through pipe 29 to flexible coupling 30 which couples to the trunnion type air cylinder 21, pivoted at 31. An application of air pressure compresses spring 32 causing roller 14 to move toward roller 4. Since air pressure exists only when the machine is in actual operation, the rollers will automatically separate should the machine stop, thereby preventing the overheating of the neoprene or other resilient material on the inner roller.

Although the magnitude of the air pressure could be used to control the pressure exerted between the co-acting ribs of the rollers, this is not done in practice. It has been found to be more satisfactory to use a high pressure to force the carriage against an adjustable stop 33, the position of the stop thereby acting to control 01' limit the pressure exerted at the surfaces of the ribs.

Thev actual position of the synchronized ribs on the two rollers also must be adjusted carefully with respect to the fingers of the bag carrier system, so that sealing of the vertical edges of the bags will be accomplished accurately. Before the bags enter the space between the vertical or side sealing. rollers they have been filled with the desired amount of tea or other substance and have also. been separated into individualbags, the material remaining in the bags only by virtue of the pairs of fingers 38 gripping both edges of the bag along its entire depth. Due to the fact that the bags are travelling in a substantially straight line as they pass between the vertical side sealing rollers, the edges of successive bags frequently touch or even overlap slightly. If the sealing ribs were pressed indiscriminately upon the edges of the bags, any that were at that instant overlapped would be sealed firmly together, necessitating manual separation. In order to eliminate this trouble, small knife like projections 34 are provided, running longitudinally of the centre of the sealing surface 25 of each of ribs [3. In each sealing surface 24 of resilient members 20 running longitudinally of the surface along its centre is a corresponding slot 35 into which the projection 34 will pass.

Projection 34 and slot 35 co-operate during the sealing process to separate the edges of successive bags from each other, preventing their being sealed together, as shown clearly in Figure 2. Since the bags are'being carried in the direction indicated by arrow 36, the bags are shown sep- 4 arated, having just previously been sealed adjacent their edges 36 and 31. Thus projections 34 and grooves 35 allow each co-operating pair of ribs to seal the adjacent edges of two successive containers simultaneously, and eliminate an otherwise duplex operation.

It will be noted that the height of the ribs on the rollers must be sufiiciently great that the recesses formed between adjacent ribs on the same roller will not interfere with the bags or carrier finger as they pass between the rollers.

It is thought that the construction and use of the invention will be apparent from the above description of the various parts and their purposes. It will be apparent that changes can be made in the arrangement, shape, or size of the various components shown without departing from the fundamental principles upon which the present invention i based, as defined in the subjoined claims.

What I claim as my invention is:

1. In a packaging machine of the character described, heat sealing means comprising a pair of cooperating rollers operatively connected together mounted with their axes in parallel relation and provided at spaced intervals around the cylindrical surface thereof with sealing ribs disposed in parallel relation to the axes of the rollers, for sealing engagement with the material advanced therebetween, means for rotating said rollers so that the ribs cooperate with each other during rotation of the rollers, one of said rollers being heated, the other roller being mounted for movement toward and away from said one roller, pneumatically operated means operative only during rotation of the rollers for moving said movable roller into sealing engagement during the operation of the machine, and resilient means arranged to automatically maintain the rollers separated when rotation of the rollers and operation of said pneumatically operated means is discontinued, said roller mounting including a slidable carriage, and stop means engageable with the carriage for limiting the movement of said movable roller towards the heated roller.

2. In a packaging machine of the character described, heat sealing means comprising a pair of cooperating rollers operatively connected together mounted with their axes in parallel relation and provided at spaced intervals around the cylindrical surface thereof with sealing ribs disposed in parallel relation to the axes of the rollers, for sealing engagement with the material advanced therebetween, means for rotating said rollers so that the ribs cooperate with each other during rotation of the rollers, one of said rollers being heated, the other roller being mounted for movement toward and away from said one roller, pneumatically operated means operative only during rotation of the rollers for moving said movable roller into sealing engagement during the operation of the machine, and resilient means arranged to automatically maintain the rollers separated when rotation of the rollers andoperation of said pneumatically operated means is discontinued, said roller mounting including a slidable carriage, and said pneumatically operated means including an air cylinder and a piston operatively connected to said carriage.

3. In a packaging machine of the character described, heat sealing means comprising a pair of cooperating rollers operatively connected together and mounted with their axes in parallel relation and provided at spaced intervals around the cylindrical surfaces thereof with sealing ribs disposed in parallel relation to the axes of the rollers for sealing engagement with adjacent edges of a series of successive individual nonconnected containers advanced therebetween, means for rotating said rollers so that the ribs cooperate with each other during rotation of the rollers, said cooperating ribs being arranged to efiect simultaneous sealing of the trailing edge of one container and the leading edge of a succeeding and closely adjacent separate container, each of the ribs of one roller having a medial longitudinal projection having a crest surface of substantial width and length and the crests of the ribs of the second roller comprising blocks of resilient material each having a corresponding slot for co-operation with a respective projection and arranged to fold portions of said closely adjacent edges into said slot to separate said edges during a sealing operation thereby to prevent sealing of said adjacent edges one to the other.

VICTOR GEORGE REFERENCES CITED The following references are of record in the file of this patent: 

